Since the land in the cities is limited, the buildings are built with more and more stories. Lower floors of the buildings need to support the weight of higher floors of the buildings. Therefore, when the buildings have more stories, the lower floors of the buildings need to support more weight. Since each material has a maximum value that the material can bear, the number of stories which the building can be built is limited based on the material the building uses.
In order to increase the stories of the buildings, the materials having lighter weight are used for decreasing the weight which the lower floors of the buildings need to support. That is, the needs for reducing the weight of the non-structural elements of the buildings are increased. In general, cement products, which are made of concrete, are heavy, so that cement products cannot meet the needs for manufacturing high-floor buildings. In addition to environmental and economical aspects, it is important to design building materials, which are light, vibration-proof, capable of insulating heat and saving energy.
According to the prior art, inorganic foam materials, for example, foam glass, foam ceramic, and foam brick, are manufactured under a high-temperature process. The temperature during the process is between 500° C. and 1200° C. Since the inorganic foam materials are sintered under the high temperature, it consumes a large amount of energy, which is environmentally unfriendly.
The inorganic foam materials are environmentally unfriendly because of wasting too much energy and consuming lots of resources during the process. In addition, the conventional process needs to be performed under high temperature, so it is difficult to control the foamability and uniformity of bubbles of the inorganic foam materials. Therefore, the foamability of the inorganic foam materials is lower than expected and the bubbles generated inside the inorganic foam materials are not uniformly distributed. Further, since it is hard to control the conditions of the process, the inorganic foam materials are worse in compressive strength, heat insulation and noise insulation.
Therefore, it is important to solve the problem that the process for manufacturing inorganic foam materials consumes too much energy.